#include<iostream>

using namespace std;
long long a,b,n,a1,b1,a2,b2,sum;
int main()
{
    cin>>a>>b>>n;

    if((n-b)%(b-a)==0){
        sum=(n-b)/(b-a)*2+1;
        cout<<sum<<endl;
        return 0;
    }
    else{
        sum=(n-b)/(b-a)+1;
        sum*=2;
        sum++;
        cout<<sum<<endl;
        return 0;
    }
    return 0;
}
